Blood pressure changes constantly depending on changes that occur in the internal and external environments. Thus, it would be ideal to continuously record individual pulses. Even if such recording cannot be performed, it would be useful if one can continuously measure blood pressure over the course of a day, carry out such measurement on a regular basis, and monitor changes in blood pressure chronologically.
When periodically measuring blood pressure with a conventional sphygmomanometer, a cuff is wrapped around an examinee's brachium. In this case, a cuff big enough to wrap around the brachium and the main body of the sphygmomanometer comprises a blood pressure measuring device. For this, the examinee must wear the cuff on the brachium, carry the entire device with him and carry out his daily routine. However, doing so would be troublesome for the examinee. Further, the examinee will feel the discomfort of the cuff applying pressure against the brachium every time blood pressure is measured.
In order to solve such inconveniences, there is proposed a measurement method using a small cuff wrapped around the fingers. In this method, it is possible to miniaturize the entire instrument since the fingers are much smaller than the brachium (non patent reference 1). In addition, there is a method of attaching a cuff on the earlobe, applying pressure to the earlobe and thereby measuring blood pressure (patent reference 1).
According to such a method which utilizes the earlobe as the test subject, it is possible to miniaturize the blood pressure measuring instrument in comparison to those designed to be wrapped around the brachium. This also improves convenience of the device for the users.                Non patent reference 1: Osamu Tochikubo, “Blood pressure measurement method and clinical evaluation”, Medical Tribune Inc. 1988, 59-61        Patent reference 1: Japanese Patent Publication Laid-Open No. 2005-6906        